Description
Background: SPARC (secreted protein acidic and rich in cysteine), also known as osteonectin and BM40, is a secreted matricellular glycoprotein that belongs to a group of functionally related glycoproteins that includes tenascins C and X, thrombospondins 1 and 2, and osteopontin (1). Members in this class of glycoproteins are involved in tissue renewal, tissue remodeling, and embryonic development and work by exerting counter-adhesive and antiproliferative effects that lead to changes in cell shape, disruption of cell adhesion, and inhibition of the cell cycle (2). SPARC is expressed at high levels in bone tissue but is widely distributed in many other tissues and cell types (3), and is known to be associated with tissues undergoing morphogenesis, angiogenesis, mineralization, and other pathological responses to injury and tumorigenesis (4,5). SPARC has also been linked with obesity and diabetes (6)